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commit 88a31ffeccce13192a474f4981b9cf6cfdfe065e
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Author: Victor Stinner <vstinner@redhat.com>
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Date:   Wed Mar 20 17:43:20 2019 +0100
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    bpo-35746: Fix segfault in ssl's cert parser (GH-11569)
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    Fix a NULL pointer deref in ssl module. The cert parser did not handle CRL
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    distribution points with empty DP or URI correctly. A malicious or buggy
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    certificate can result into segfault.
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    Signed-off-by: Christian Heimes <christian@python.org>
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    https://bugs.python.org/issue35746
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    (cherry picked from commit a37f52436f9aa4b9292878b72f3ff1480e2606c3)
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    Co-authored-by: Christian Heimes <christian@python.org>
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diff --git a/Lib/test/talos-2019-0758.pem b/Lib/test/talos-2019-0758.pem
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new file mode 100644
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index 0000000..13b95a7
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--- /dev/null
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+++ b/Lib/test/talos-2019-0758.pem
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@@ -0,0 +1,22 @@
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+-----BEGIN CERTIFICATE-----
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+MIIDqDCCApKgAwIBAgIBAjALBgkqhkiG9w0BAQswHzELMAkGA1UEBhMCVUsxEDAO
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+BgNVBAMTB2NvZHktY2EwHhcNMTgwNjE4MTgwMDU4WhcNMjgwNjE0MTgwMDU4WjA7
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+MQswCQYDVQQGEwJVSzEsMCoGA1UEAxMjY29kZW5vbWljb24tdm0tMi50ZXN0Lmxh
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+bC5jaXNjby5jb20wggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQC63fGB
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+J80A9Av1GB0bptslKRIUtJm8EeEu34HkDWbL6AJY0P8WfDtlXjlPaLqFa6sqH6ES
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+V48prSm1ZUbDSVL8R6BYVYpOlK8/48xk4pGTgRzv69gf5SGtQLwHy8UPBKgjSZoD
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+5a5k5wJXGswhKFFNqyyxqCvWmMnJWxXTt2XDCiWc4g4YAWi4O4+6SeeHVAV9rV7C
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+1wxqjzKovVe2uZOHjKEzJbbIU6JBPb6TRfMdRdYOw98n1VXDcKVgdX2DuuqjCzHP
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+WhU4Tw050M9NaK3eXp4Mh69VuiKoBGOLSOcS8reqHIU46Reg0hqeL8LIL6OhFHIF
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+j7HR6V1X6F+BfRS/AgMBAAGjgdYwgdMwCQYDVR0TBAIwADAdBgNVHQ4EFgQUOktp
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+HQjxDXXUg8prleY9jeLKeQ4wTwYDVR0jBEgwRoAUx6zgPygZ0ZErF9sPC4+5e2Io
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+UU+hI6QhMB8xCzAJBgNVBAYTAlVLMRAwDgYDVQQDEwdjb2R5LWNhggkA1QEAuwb7
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+2s0wCQYDVR0SBAIwADAuBgNVHREEJzAlgiNjb2Rlbm9taWNvbi12bS0yLnRlc3Qu
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+bGFsLmNpc2NvLmNvbTAOBgNVHQ8BAf8EBAMCBaAwCwYDVR0fBAQwAjAAMAsGCSqG
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+SIb3DQEBCwOCAQEAvqantx2yBlM11RoFiCfi+AfSblXPdrIrHvccepV4pYc/yO6p
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+t1f2dxHQb8rWH3i6cWag/EgIZx+HJQvo0rgPY1BFJsX1WnYf1/znZpkUBGbVmlJr
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+t/dW1gSkNS6sPsM0Q+7HPgEv8CPDNK5eo7vU2seE0iWOkxSyVUuiCEY9ZVGaLVit
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+p0C78nZ35Pdv4I+1cosmHl28+es1WI22rrnmdBpH8J1eY6WvUw2xuZHLeNVN0TzV
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+Q3qq53AaCWuLOD1AjESWuUCxMZTK9DPS4JKXTK8RLyDeqOvJGjsSWp3kL0y3GaQ+
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+10T1rfkKJub2+m9A9duin1fn6tHc2wSvB7m3DA==
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+-----END CERTIFICATE-----
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diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py
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index f7a6746..31af578 100644
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--- a/Lib/test/test_ssl.py
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+++ b/Lib/test/test_ssl.py
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@@ -68,6 +68,7 @@ WRONGCERT = data_file("XXXnonexisting.pem")
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 BADKEY = data_file("badkey.pem")
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 NOKIACERT = data_file("nokia.pem")
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 NULLBYTECERT = data_file("nullbytecert.pem")
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+TALOS_INVALID_CRLDP = data_file("talos-2019-0758.pem")
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 DHFILE = data_file("dh1024.pem")
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 BYTES_DHFILE = DHFILE.encode(sys.getfilesystemencoding())
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@@ -238,6 +239,27 @@ class BasicSocketTests(unittest.TestCase):
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                          ('IP Address', '2001:DB8:0:0:0:0:0:1\n'))
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                         )
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+    def test_parse_cert_CVE_2019_5010(self):
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+        p = ssl._ssl._test_decode_cert(TALOS_INVALID_CRLDP)
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+        if support.verbose:
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+            sys.stdout.write("\n" + pprint.pformat(p) + "\n")
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+        self.assertEqual(
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+            p,
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+            {
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+                'issuer': (
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+                    (('countryName', 'UK'),), (('commonName', 'cody-ca'),)),
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+                'notAfter': 'Jun 14 18:00:58 2028 GMT',
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+                'notBefore': 'Jun 18 18:00:58 2018 GMT',
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+                'serialNumber': '02',
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+                'subject': ((('countryName', 'UK'),),
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+                            (('commonName',
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+                              'codenomicon-vm-2.test.lal.cisco.com'),)),
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+                'subjectAltName': (
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+                    ('DNS', 'codenomicon-vm-2.test.lal.cisco.com'),),
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+                'version': 3
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+            }
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+        )
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+
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     def test_parse_all_sans(self):
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         p = ssl._ssl._test_decode_cert(ALLSANFILE)
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         self.assertEqual(p['subjectAltName'],
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diff --git a/Modules/_ssl.c b/Modules/_ssl.c
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index 6220bea..baea6e1 100644
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--- a/Modules/_ssl.c
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+++ b/Modules/_ssl.c
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@@ -1103,6 +1103,10 @@ _get_crl_dp(X509 *certificate) {
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         STACK_OF(GENERAL_NAME) *gns;
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         dp = sk_DIST_POINT_value(dps, i);
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+        if (dp->distpoint == NULL) {
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+            /* Ignore empty DP value, CVE-2019-5010 */
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+            continue;
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+        }
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         gns = dp->distpoint->name.fullname;
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         for (j=0; j < sk_GENERAL_NAME_num(gns); j++) {